Disc playing system with continuous playing function

ABSTRACT

An automatic disc playing system for playing selected ones of a plurality of discs stored therein in succession, includes a disc storing part for holding the discs, having a plurality of slots juxtaposed in a predetermined direction, a detection means for detecting the presence or absence of a disc in each of the slot, and a memory means for memorizing the number of vacant slots in accordance with the output signal of the detection means. The detection means is made up of a plurality of members provided to each of the slots, to be shifted when a disc is put in the slot, and a sensor means to be moved along the direction of the arrangement of the slots for detecting the position of each of the members provided to the slots.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a disc playing system, and moreparticularly to a disc playing system which stores a plurality of discsand capable of continuous playing of discs in order which discs arearbitrarily selected from the stored discs.

2. Description of Background Information

As an example of the disc playing system of this type, a disc displayingsystem is described in Japanese Patent Application No.56-67396corresponding to U.S. patent application Ser. No. 373,123 filedMay 2, 1982. In this disc playing system, a plurality of discs arestored in a disc storing part and juxtaposed at a predetermined space. Adisc playing means is provided to be slidable along the direction of thearrangement of the discs, and a detection means is provided fordetecting the position of the disc playing means relative to eachstoring slot of the disc storing part. The disc playing means istranslated along the direction of the disc arrangement and stop positionis controlled in accordance with the output signal of the light sensorso that the disc playing means stops at the position of a selected disc.The playing of the selected disc is parformed after the disc is movedfrom the disc storing part to the playing position by means of a disctransportation means.

A disc presence or absence sensor is provided in the middle of the routeof the movement of the disc from the disc storing part to the playingposition and the detection of the presence or absence of a disc in aselected disc storing slot is performed in such a manner as to detectwhether or not the passing of a disc is sensed within a predeterminedtime period after the start of the operation of the disc transportationmeans. If it is detected that no disc is present in the selected discstoring slot, then the number of the slot is memorized in the memorymeans. Thus, further designation of the disc storing slot having no discis prevented and as a result the discs are played in sequence verysmoothly.

Since this conventional disc playing system is constructed in thismanner, there is an advantage that the disc storing slot with no disc isno selected twice. However, at the time of first selection of such adisc storing slot, the playing means is moved to the position of theselected slot and the disc translation means is actuated until theabsence of the disc is sensed. Thus, there is a drawback that theelectricl engergy is consumed by the movement of the playing means andthe disc transportation means and also a time period is consumed by theabove process.

Further, in the case of the disc playing system of Japanese Patentapplication No. 57-45276 proposed by the present applicant, a scaning iseffected through all of the disc storing slots at the time of throw-inof the power current and the numbers of the vacant disc storing slot arememorized. However, also in this type of disc playing system, there isthe same problem that the disc transportation means is moved to theposition of each disc storing slot and the output signal of the discpresence sensor is observed each time. Thus a long time period isrequired before the selection of the disc becomes possible after thethrow-in of the power current.

SUMMARY OF THE INVENTION

A objec of the invention is therefore to provide a disc playing systemwhich is capable of detecting the vacant disc storing slot at a veryhigh speed.

According to the present invention, the detection means for detectingthe presence of a disc in each disc storing slot of the disc storingpart is made up of displacement members provided to each of the discstoring slots and adapted to shift when a disc is stored in the slot,and a sensor means movable along the direction of the arrangment ofdiscs and adapted to detect the shift of the displacement member inorder.

Further scope and applicability of the present invention will becomeapparent from the detailed description given hereinafter. However, itshould be understood that the detailed description and specificexamples, while indicating preferred embodiments of the invention, aregiven by way of illustration only, since various changes andmodifications within the spirit and scope of the invention will becomeapparent to those skilled in the art from this detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing the general construction of thedisc playing system of the present invention;

FIGS. 2A through 2c are respectively, a plan view, a partially sectionalfront view, and a cross sectional side view of the control unit to beused with the main unit, both shown in FIG. 1;

FIGS. 3A through 3C are respectively, a plan view, a front view, a sideview of the main unit;

FIG. 4 is a general perspective view of the disc storing part;

FIGS. 5A and 5B are reapectively a partially cross-sectional front viewand a cross sectional side view of the disc storing part;

FIGS. 5C and 5D are respectively a perspective view of a displacementmember provided in the disc storing part, and a cross-section takenalong the line A--A of FIG. 5A;

FIGS. 6A and 7A are plan views of a disc stopper respectively in theposition for preventing the movement of the discs and in the positionfor allowing the movement of the discs;

FIGS. 6b and 7B are side views of the disc stopper respectivelycorresponding to FIGS. 5A and 6A;

FIGS. 8A and 8B are respectively a plan view and a front view of aslider portion;

FIGS. 9A through 9C are respectively a partially cross-sectional planview, a partially cross-sectional front view, a side view of a clamper;

FIG. 10 is a block diagram showing the construction of a control systemof the disc playing system;

FIG. 11 is a block diagram of a door control part;

FIGS. 12A through 12D are diagrams showing the steps of music selectionoperation;

FIG. 13 is a flowchart showing the operation of the disc playing system;

FIGS. 14A through 14c are diagrams showing the operation of the slider;

FIGS. 15A and 15B are respectively a plan view and a front view showingthe relative position of each part during a period for the detection ofthe presence or absence of the disc and the detection of the disc side;

FIG. 16 is a diagram showing the relation between the positions of thedisc in the disc storing part and in the playing position; and

FIGS. 17A and 17B are waveform diagrams showing the output signals ofthe slot position sensor and the disc presence sensor produced when thecarrer is moved along the disc storing part.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The invention will be explained with reference to the accompanyingdrawings hereinafter.

FIG. 1 is a perspective view of the disc player system of the inventionin which the general structure of player system is illustrated. In FIG.1, the player system includes a housing of a main unit 4 in which aplurality of discs 2 are housed and the discs are played automatically.The housing has a construction suited for stacking with other appliancessuch as an amplifier and a tuner of similar size. A disc entrance port 3is formed, for example, in the front face of the housing. A disc holder(to be explained later) is provided near to the disc entrance port 3 sothat the discs are loaded and removed with ease. A door 5 for closingthe disc entrance port 3 is connected to the housing. The opening andclosing of the door is performed by means of a door switch 6 mounted inthe front face of the housing. Also, there is provided a control unit 6which transmits various commands to the main unit 4 and connected to themain unit 1 via a wire or wireless connection means.

FIGS. 2A through 2C show the construction of the control unit 6, inwhich FIG. 2A is a plan view, FIG. 2B is a partially sectional frontview, and FIG. 2C is a side view respectively. The control unit 6 has aplurality of operation keys thereon. The keys comprise number keys 7 towhich the numbers 0 through 9 are alloted for the designation of thenumber of disc and the number of music to be selected, an ENT key 8 forregistering the selected number in a memory means, an ALL key 9 for theselection between a play mode for playing the discs in order from afirst disc and a play mode for playing all of the designated discs, aSTART key 10 for starting the play after completion of the designationin the memory means, a NEXT key for commanding the shift to the nextdisc/music registered in the next position in the memory means while adisc/music registered in the memory means is being played, and an AGAINkey 12 for commanding the replay of the music in accordance with thecontents registered in the memory means. Further the control unit 6 hasa plurality of index plates 13 on which the title or the program can beentered and altered in connection with the replacement of the discs, andoperatable as a memory means which is easy to look up, a plurality ofindex switches 14 for picking out one of index plates 13 being searchedfor, with the index switch 14 interlocked with the index plates 13, andprepared as many as the number of index plates 13, and a plurality ofindex keys 15 from number 1 through number 5 for designating the discnumber separately from the number keys 7. As mentioned above, the titleor the program name on the index plates 13 can be altered easily inrelation to the replacement of the discs.

In addition, both main unit 4 and control unit 6 are respectivelyprovided with a display device which comprises a DISC indicator 16 fordisplaying the number of the disc designated or being played, a PROGRAMindicator 17 for displaying the number of the program designated orbeing played, a PLAY indicator 18 for displaying the playing state, aSTAND BY indicator 19 which lights up from a time when a carrierassembly (described later) is stopped at a predetermined position to atime when the carrier assembly is in playing state, an ACCESS indicator20 which lights up during a time when the carrier assembly and a pickup(described later) are moving to a predetermined position, and an ERRORindicator 21 which lights up when the disc is not present in a positionof designated disc number, or the disc is placed reversely and such astate is detected in the playing state.

Although the control unit 6 with a memory means and verious operationkeys is prepared separately from the main unit 4 in the above explainedexample, these elements may be provided to both of the main unit 4 andthe control unit 6 or solely to the main unit 4, in the front face forexample.

FIGS. 3A through 3C show the construction of the disc player system,where FIG. 3A is a plan view, FIG. 3B is a front view, and FIG. 3C is aside view. Before explaining the internal construction, the peripheralportion of the door 5 previously mentioned is covered by paint forexample. Further, the door is provided with a pair of support pins 23a,23b fixed to the under base 22 and a pair of bearings 24a, 24brespectively engageable with the support pins 23a, 23b. A sectoral gear25 is connected to one, for example the bearing 24a of the bearings 24aand 24b. A drive motor 26 and a reduction gear 27 for opening andclosing the door 5 are provided and secured on the under base 22. A gear28 of the final stage of the reduction gear 27 is meshed with thesectoral gear 25. A cam 30 having a recess 30a on the outer surface isfixed on a shaft 28 of the gear 28 of the final stage. A pair of limitswitches 31a and 31b each having a cam follower are provided and abutagainst the outer surface of the cam 30 so as to detect an open limitand a close limit of the door 5 when the cam follower is received in therecess 30a.

As shown in the perspective view of FIG. 4, a disc storing part 32 forstoring a plurality of discs comprises a support base 34 having aplurality of grooves 33 and fixed to the under base 22 and a pluralityof partition plates 35. The discs 2 are placed between the partitionplates 35 and supported in the grooves, thus uprightly juxtaposed witheach other. The support base 34 is made by a member of single piece anda pair of supports 36, 37 for bearing the lower end of a disc 2 placedin the groove 33 at two points, and for the positioning of the disc 2 inthe longitudinal direction of the slot 33 are provided in the front andin the rear of the support base 34, for example, as a solid block. Theheight of the support 36 of the front side (on the side of the discentrance port 3) is made higher than the support of the rear side so asto prevent the discs 2 from falling out from the front side due to anexternal disturbance, and at the same time to restrain the free movementof the stored discs. In addition, the supports 36, 37 may be prepared asseparate parts with respect to the support base 34.

In the disc storing part 32, each of the discs 2 is held in a slotformed between two adjacent partition plates 35. As shown in FIGS. 5Aand 5B, each slot is provided with a displacement member 38 which isdesinged to shift when a disc is put in the slot. The displacementmember 38 has, as clearly shown in FIG. 5C, a bearing head 38a with aconcave upper face, a shutter plate 38b and a connecting rod 38c forconnecting the bearing head 38a and the shutter plate 38c, and supportedby the support base 34 at the connecting rod 38c thereof so as to movefreely in the vertical direction. Further a spring is provided betweenthe bearing head 38a and the support base so as to urge the displacementmember 38 upwardly. Thus, when the disc is not present in the slot, thelower end of the shutter plate 38b of the displacement member 38 islocated almost on the level of an upper reference line A. When the discis present, the displacement member 38 is moved down against theresilient force of the spring 39 by the weight of the disc and in thisstate an upper edge of e shutter plate 38c is almost on the level of theupper reference line A and the lower edge of the shutter plate 38c isalmost on the level of a lower reference line B.

On the other hand, a holder 51 which carries a slot position sensor 50aand a disc presence sensor 50b thereon is fixed to the carrier 40 via aconnection member 52 so as to move in the direction of the arrangementof the discs together as the movement of the carrier 40 which is shownin FIG. 3. The slot position sensor 50a is mounted on the holder 51 atthe level of the upper reference line A so as to detect the position ofeach slot when moved along the line A as the movement of the carrier 40.Similarly, the disc presence sensor 50b is mounted on the holder 51 atthe level of the lower reference line B so as to detect the postion ofthe displacement member 38 i.e., the presence or absence of the disc inthe slot when moved along the line B. The slot position sensor 50a andthe disc presence sensor 50b are spaced on the holder 51 at a distance 1which is substantially equal to the space of the disc in the discstoring part 32.

As shown in FIG. 5D the slot position sensor 50a and the disc presencesensor 50b are respectively made up of a light emitting element and alight receiving element which are faced with each other so as to form agap therebetween in which the shutter plate 38c is located. Since theoutput signal of the sensor 50a is in the form of a pulse train each ofthe pulse thereof corresponds to the position of the slot, the postionof the carrier 40 relative to the position of the slots can be detected,for example, by counting the trailing edge of each pulse.

In FIG. 3, a carrier 40 for supporting a disc playing part is slidablymounted on a pair of guide bars 42a, 42b at round holes 41a and ovalholes 41b provided in side portions thereof. The carrier 40 is providedwith a guide support 43 which has thereon a concave part for thepositioning of the disc drawn from the disc storing part 32 by means ofa slider to be described later, at the time of playing. The guidesupport 43 is adapted to support the lower periphery of the disc at twopoints in a manner that the center of the disc mounted thereon isslightly lower than the center of a clamper which will be described indetail later. The guide support 43 is provided with a slope 43a on theside of the disc storing part 32 so that the disc is moved smoothly.Further, a slope can also be provided on another side of the guidesupport so that the disc can be returned to the playing position surelyin the event that the disc is dislocated backwards from the playingposition.

The carrier 40 is moved in the left and right direction by means of adrive motor 44 via a reduction gear 45 and a wire 46. The wire 46 isspreaded on a pulley connected to the reduction gear 45, four pulleysmounted on the under base 22, and a magnet 48d, and fixed to the carrier40. To detect a left limit and a right limit of the movement of thecarrier 40, there are provided a pair of carrier limit switch 49a, 49b.Assuming that a siding position of the carrier 40, i.e., a home positionis in the right hand end of FIG. 3, then the carrier limit switch 49acan be used for detecting that the carrier 40 is in the home position.Further, a carrier position detection sensor 50 is provided to detectthe shift amount of the carrier 40. The carrier position detectionsensor 50 has an elongated slit plate 51 fixed to the under base inwhich a slit is formed along the direction of the movement of thecarrier 40 correspondingly to the disc storage position of the discstoring part 32, and a light sensor 52 having a light emitting elementand a light receiving element and mounted on the carrier 40 in such amanner as to put the slit plate 51 in a gap formed therein.

A mechanism base 53 is fixed on the carrier 40 and which carries thereonvarious parts such as a disc drive motor 54 for rotating the disc, apickup 55 for the readout of disc information movably supported on themechanism base 53, a pickup drive motor 56 and a reduction gear 57 formoving the pickup, a slider 58 for drawing out a disc stroed in the discstoring part 32, a guide base 59 for guiding and supporting the slider58. Further, as a means for playing the disc, a carrier assembly 64 ismade up of a pair of guide plates 60a, 60b for guiding the disc drawnout from the disc storing part 32 to the playing position, a disc sidesensor 61 fixed on one of the guide plates 60a, 60b for detecting theside of the disc, and a clamp arm on which a clamper 62 for holding thedisc is mounted.

The pickup 55 is supported by a pair of guide bars 65a and 65b fixed onthe mechanism base 53 so as to move in the radial direction of the disc.The drive force of the pickup drive motor 56 is transmitted to thepickup 55 via a cable 68 fixed thereto and spread on a pulley 66connected to the reduction gear 57 and a pulley 67 fixed on themechanism base 53. To detect the inner limit position and the outerlimit position of the pickup 55 with respect to the disc, pickup limitswitches 69a, 69b are provided.

The pair of guide plates 60a, 60b are supported to keep a predeterminedspace therebetween by means of a stopper pin 70 (shown in FIG. 15)prepared behind the guide plates 60a, 60b for preventing the discs fromslipping off backwards. An end of the guide plates 60a, 60b facing thedisc storing part 62 are bent outwards so that the deviation of theposition of the carrier assembly 64 relative to the disc storing part 32from a proper position can be neglected and the disc is surely guided tothe playing position, and also that the leaning of the disc in theplaying position is prevented. Although a relatively thin plate materialis used as the guide plates 60a, 60b and an end of each plate is bentoutwards with respect to each other in this embodiment, thick membersmay be used instead of the thin plates and in such a case a slope may beprovided to the end of the thick members so that the space between themembers gradually increases toward the tip of the members.

In FIG. 3, a disc stopper 71 is provided behind the disc storing part 32so as to prevent the discs from getting off from the disc storing part32, as being supported and positioned on a pair of stopper arms 72rotatably supported by the under base 22. The stopper arm 72 is providedwith a pin 74 which is engageable with a cam plate 73 projecting fromthe carrier 40. When the carrier assembly 64 is in the right limitposition of FIG. 3A i.e., the home position, the pin 74 comes to contactwith the cam plate 73 of the carrier 40 as shown in the front view ofFIG. 6A and the side view of FIG. 6B, to locate the disc stopper 71 in astop position for preventing the movement of the discs 2. Conversely,when the carrier assembly 64 is dislocated from the home position, thepin 74 is disengaged with the cam plate 73 as seen in the front view ofFIG. 7A and the side view of FIG. 7B, to cause the rotation of the discstopper 71 in counter clockwise direction. Thus the disc stopper 71 issided from the stop said stop position mentioned above.

The disc stopper 71 is arranged to have the aforementioned stop positionwithin limits in which the disc can return to the position on thesupports 36, 37 when the disc is dislocated backwards. Further the discstopper 71 can be arranged to be in contact with the discs when thediscs are on the supports 36, 37. When the discs are installed in thedisc storing part 32, the disc stopper 71 operates as a stop againstwhich the discs abut, to prevent the dislocation of the discs. Also, thestopper 71 acts as a restraining member for preventing the movement ofthe discs 2 from the disc storing part 32 due to the externaldisturbance or vibration when the player system is kept unused. Inaddition, the restraining member can be prepared separately from thedisc stopper 71 and various arrangements can be utilized for such arestraining member.

FIGS. 8A and 8B show the construction of the slider part, where FIG. 8Ais a plan view and FIG. 8B is a front view. As shown, in the upper faceof the guide base 59, there are provided, for example, three guideglooves 75a, 75b, and 75c, in which three guide pins 75a, 75b, 75cconnected to the slider 58 is allowed to linearly slide with respect tothe guide base 59.

On the slider 58, a pair of arms 77a and 77b are provided whichrespectively carry a drawer sheave or roller 78 and a reset sheave orroller 79. The drawer roller 78 and the reset roller 79 are spaced at apredetermined distance in the direction of the movement of the sliderand adapted to contact with the pheripheral edge of disc in a mannerthat the pheripheral edge of the disc is put in a groove portion of theroller. The drawer roller 78 and the reset roller 79 operate as atransportation member for transporting the disc form the disc storingpart 32 to the playing position and vice versa by rotating the disc.

In order to drive the slider 58, a drive motor 80 and a worm gear 83connected thereto through a belt 81 and a pulley 82 are mounted on theguide base via a chassis 84. The worm gear 83 is meshed with a main gearto which a pulley 86 is coaxially connected. A wire 87 is wound aroundthe pulley 86 and connected to the slider 58 via a couple of pulleys88a, 88b provided at both ends of the guide base 59, so as to move theslider 58. Further, a pair of slider limit switches 89a, 89b fordetecting the limits of the slide movement of the slider 58 bycontacting with a cam projection 58a of the slider 58, and a discdetection position switch 89c for detecting the position for thedetection of the presence and the side of the disc.

FIGS. 9A through 9C show the construction of the clamper where FIG. 9Ais a partially cross-sectional plan view, FIG. 9B is a partiallycross-sectional front view, and FIG. 9C is a side view. As shown, abearing frame 90 is provided to the carrier 40 (shown in FIG. 3) and aclamp arm 63 is rotatably mounted on a shaft 91 connected to the bearingframe 90. A spring 92 is provided for urging the clamp arm 63 inclockwise direction in the figures. The range of the rotation of theclamp arm 63 is restricted by means of a pin 93 projecting from thebearing frame 63. The clamp arm 63 is provided with a guide part 95 witha magnetic part 94 at an end thereof and a guide pin 96 for governingthe rotation of the clamp arm 93 in the clockwise i.e., the closingdirection. When the carriage member is located in the playing position,the guide pin 96 is received in the guide slot 97a of an engaging member97 provided to the slider 58 (shown in FIG. 8A) and moves through theguide slot 97a to cause the rotation of the clamp arm 63 against theresilient force of a spring 92. The clamper 62 having substantially atruncated cone form is provided with a ring magnet 98 at the base partthereof and a magnetic member 99 at the head part thereof, and looselyreceived in the clamp arm at a guide part 95 thereof. In addition, theclamper 62 and the clamp arm 63 are made of a non-magnetic material.

The drive motor 54 for rotating the disc 2 is mounted on a part of themechanical base 53 facing the clamper 62. A turntable 100 operatable asa disc drive means is mounted on a spindle of the motor 54 and in whicha ring magnet 101 and an yoke 102 are housed.

With the thus constructed clamper portion, when a disc is loaded in theplaying position, the clamp arm is in turn rotated in the closingdirection, as the result of an engagement of the guide pin in the guideslot 97a of the engaging member 97 provided to the slider 58. As therotation of the clamp arm 63, the head portion of the clamper 62 passesthrough a center hole of the disc 2 and inserted into the turntable 100.In this instance, the magnetic material 99 of the head portion of theclamper 62 forms a magnetic circuit along with the magnet 101 and theyoke 102 in the turntable 100 so that the magnetic material is attractedto the yoke 102. As the advancement of the clamper 63, the disc 2carried on the support guide 43 is held up by the tapering part of theclamper 62 and clamped on the face 100a of the turntable 100. The clamparm 63 is further rotated to disengage the guide part 95 from theclamper 62 which has been coupled with the guide part 95 by theattraction force between the magnetic member 94 and the magnet 98. Asthe result, the disc clamping force between the magnetic member 99 andthe yoke 102 is reinforced by the attraction force between the magnet 94mounted on the base part of the clamper 62 and the magnetic member 94eclamper 62. In this state, the clamper 62, disc 2, and the turntable 100are mechanically isolated from (do not contact with) other parts and astable rotation of the disc 2 is secured.

Turning to the block diagram of FIG. 10, the control unit of the discplaying system according to te present invention will be explainedhereinafter. The control unit 6 is provided with a group of switches 601of music selection for designating the number of disc or the number ofthe piece of music as explained with referance to FIG. 2, and a displaypart 602 for displaying the number of the piece of music, and the modeof operation of the system. The control unit which comprises a CPU 603,a ROM 604 in which a program for the operation of the system is storedand a RAM for temporarily storing calculated results is connected to theabove mentioned group of switches 601 and to the display part 602 via aninput/output interface 606 and an output interface 607. The group ofswitches 601 is made up of a plurality of switches which are arranged asthe keyboard matrix and the actuation of each switch is detected by akey scanning operation through the input/output interface 606. Thus, thekey input is effected by using a small number of connection wires. Aswitch of the switch group 601 which is actuated by an operator of thesystem is distinguished by the switch key scanning and displayed on thedisplay device 602, and in turn written in the RAM 605.

In the main unit 4 of the system, there are provided a control parthaving a CPU 401, RAM 402, and a ROM 403 like a control unit 6, an inputinterface 404, an output interface 405, a drive circuit 406, a drivenpart 407, and a source of input signals 408.

The driven part 407 includes a carrier drive motor 44 for moving thecarrier to a position of a designated disc, a slider drive motor 80 formoving a disc from the storing position and loading the same in theplaying position, a disc drive motor for rotating the disc, a pickupdrive motor 56 for moving the pickup in a radial direction of the disc,and various displaying devices.

The source of input signals 408 includes the carrier position sensor 50which, for example, consists of an optical means for detecting thecarrier position, the carrier limit switches 49a and 49b provided so asto prevent the dislocation of the carrier, the slider limit switches forrespectively detecting that the disc is in the storing position and inthe playing position, the disc presence and disc side sensor 61 fordetecting the presence or absence of the disc and determining the sideof the disc, the disc detection position switch 89c for detecting theposition of the operation of the disc presence and disc side sensor 61,pickup limit switches 69a, 69b for respectively detecting that thepickup is in the innermost position or in the outermost position, a discdrive motor speed sensor 1 for detecting that the speed of the discdrive motor is above a predetermined speed, and an information detectionpart which detects signals indicative of the inner most part of therecording tracks and the outermost part of the recording tracks, and aninformation of the number of recorded music piece, from a control signaldetected from the disc via a predetermined demodulation circuit.

Two bit signals are used and applied to the drive circuit 406 for thecontrol of the forward roatation, the backward rotation, and thestoppage of each motors. As an example, combinations (00), (01), and(10) may be used respectively as the representation of the stoppage, theforward rotation, and the backward rotation. In addition, for thepurpose of speed control, one bit indicative of a high speed and a lowspeed of rotation can be added to the above combination. In that case,combinations (000), (001), (010), (101), and (110) may respectivelyrepresent the stoppage, the forward rotation at the low speed, thebackward rotation at the low speed, the forward rotation at the highspeed, and the backward rotation of the high speed. Further, it ispossible to use a multi bit digital signal and a speed control meanshaving a D/A (digital to analog) converter acceptable the multi bitdigital signal.

The main unit 4 and the control unit 6 are connected by means of abi-directional data transmission system 460 and the CPUs 401 and 603perform the handshaking signal transmission of a predetermined codedparallel data and the timing signal of data transmission via aperipheral interface adapters (PIA) 409 and 608.

After throw-in of the power current, the main unit 4 drives the variousparts of the mechanism at initial states to cause, for example, thestoppage of the disc drive motor 54, the releasing of the slider, thepositioning of the carrier at the home position. After completion of theinitial setting the main unit 4 requires the transmission of the discnumber to the control unit via the bi-directional data transmissionsystem 460. In response to the actuation of the START key 10 (shown inFIG. 2A) after the programming of the playing order, the control unit 6transmits the data as to the number of the disc to be played first tothe main unit 4 via the bi-directional transmission system 460. Then themain unit drives the carrier 40 so that the position of the carriercorresponds to the desigated disc number. The control of the stopposition of the carrier 40 is performed, for example, by the comparisionbetween a count signal of the output signal of the position sensor 50disposed on the carrier 40 with a predetermined reference count numberwhich is corresponding to a storing position of the designated disc.During this operation, the main unit 4 transmits to the control unit 6data for displaying ACCESS via the bi-directional data transmissionsystem 460 so that the main unit 4 and the control unit 6 display thesign indicative of the ACCESS operation in process.

When the carrier 40 arrives at the designated position and stops at theposition, then the slider motor 58 starts to rotate and in turn theselected disc is loaded to the playing position. In this state, when thedetection position switch 89c disposed in the middle postion of the discloading mechanism is actuated, the output signal of the discpresence/disc side sensor 61 is entered and the loading of the disc iscontinued only when the proper side of the disc is detected. Conversely,if no disc has been set or the reverse side of the disc is detected,then the loading mechanism starts the revese operation to stop theloading. At the same time, a sign of error is displayed in the displaydevice.

The disc loaded in the playing position is then clamped by the clamper62, and the disc drive motor 54 starts to rotate. When the speed of thedrive motor 54 has reached a predetermined level, the main unit requiresthe transmission of the data as to the number of the designated musicpiece to the control unit 6. After the transmission of the designatedmusic number, the number is compared with the numbers of music pieces inthe disc, and the pickup 55 is rapidly moved at a head portion of theselected music piece. If the designated music number is greater than thenumber of music pieces contained in the disc, the pickup limit switch69b on the outermost side is actuated, thus it is determined that thedesignated music piece can not be found. In this condition, the pickup55 is stopped and then moved at a high speed to the innermost position.Also in this condition, the display of the error will be effected.

When the pickup is moved to the position of the designated music piece,playing of the music is then started. At the same time, the display ofthe playing is effected in the display part. When the playing of thedesignated music piece is completed (when the number n+1 of a musicpiece greater than the number of the designated music piece by one isdetected), the display of the playing is stopped and the main unitrequires the number of music piece to be played next. Thus, the systemstarts the playing of the next one of the music pieces. If the disc tobe played next is not the same as the disc being played presently, thenthe carrier is moved to the position of the new disc in a manner aspreviously explained, and the disc is loaded in the same manner as thedescribed. If the disc to be played next is the same as the disc beingplayed, then the main unit requires the transmission of the number ofprogram (music), and the playing is started after the transmission ofthe number of program.

Referring to the block diagram of FIG. 11, the circuit arrangement ofthe control unit of the door 5 will be explained. As shown, the doorswitch 1 disposed in the front face of the main unit 4 produces a pulsesignal through a differentiating circuit which comprises resistors R₁₁₁,R₁₁₂, and capacitors C₁₁₁, C₁₁₂. This pulse signal is applied to an ANDgate 110 together with an output signal of the carrier limit switch 49afor detecting that the carrier 40 is in the home position. An outputsignal of the AND gate 110 is then applied to a T flip flop 111 as aclock signal. Output signal at two output terminals Q, Q of the T flipflop 11 are respectively applied to an AND gate 113 together with anoutput signal of the door open limit switch 31a and to an AND gate 114together with an output signal of the door close limit switch 31b.Output signals of the AND gate 113 and the AND gate 114 are applied tothe door drive motor 26 through the drive circuit 112 as a signalindicative of the forward rotation and a signal indicative of thebackward rotation. A power reset signal is applied to a reset terminalof the T flip flop 111.

With the thus constructed control part, the reset signal is produced atthe time of throw-in of the power current irrespective of the operationof the door open/close limit switches 31a, 31b, or the position of thecarrier, and the T flip flop 111 is set such that the Q=L, Q =H.Therefore, the door motor drive motor 26 is rotated reversely or in thebackward direction to close the door, until the L level signal isproduced by the close limit switch 31b. The output signal of the doorswitch 1 which is produced when operated, is effective only when theswitch 49a produces the L level signal (indicating that the carrier 40is in the home position), and the output signal state of the T flip flop111 is inverted in that state, to drive the door drive motor 26 in theforward direction until the L level signal is produced by the door openlimit switch 31a (indicating that the door is closed) or to drive thedoor drive motor 26 in the backward direction until the L level signalis produced by the door close limit switch 31b (indicating that the dooris fully open). As will be appreciated from the foregoing, the doorcontrol unit is constructed to allow the opening of the door only whenthe carrer which carries the playing system is in the home position.Therefore, it is quite advantageous for preventing such an inconveniencethat a new disc is inserted in the storing position of the disc beingloaded in the playing position.

The operation of the disc player system having the above explainedconstruction will be further explained. As for the setting or thestoring of discs, the operation is simplified because the door 5 isopened automatically when the door switch 1 is operated, and the discstoring part 32 located behind the door 5 becomes readily accessible. Toset a disc, the system simply requires to place the disc in any of thespaces formed between each adjacent partition plates 35. In this state,since the disc stopper 71 is positioned in the stop position by theengagement with the cam plate 73 of the carrier 40 (as shown in FIG. 6),the inserted disc is prevented from being droping off backward andsurely set in the disc storing position. In addition, the searching ofthe desirable disc or program will be facilitated by entering the titleof the disc in the corresponding index plate provided in the controlunit 6 and the program names in the MEMO part 13b thereof. When thestoring of the disc are completed, and the door switch 1 is pressed oncemore, the door 5 is closed automatically to cause the closure of thedoor close limit switch 31b. In response to the output signal of thedoor close limit switch 31b,the slot position sensor 50a and the discpresence sensor 50b interlocked with the carrer 40 are started to movefor the detection of the presence of the disc in each disc storing slotof the disc storing part 32.

Assuming that the fourth disc storing slot is vacant, the detectiontakes place in the following manner. Firstly, the carrier 40 is moved inthe direction that the number of the disc increases. In this state,according to the position of each displacement member 38 provided perslot, the output signals of the slot position sensor 50a and the discpresence sensor 50b vary as illustrated in the waveform diagrams ofFIGS. 17A and 17B. Since the position of the sensors are spaced almostby the amount equal to the pitch of the arrangement of the discs, theoutput signal fo the disc presence sensor 50b is produced with a delayof the time corresponding to one disc relative to the output signal ofthe slot position sensor 50a. Althrough the output signal of the discpresence sensor 50b is synchronized with the output signal of the slotpostion sensor 50a, the signal shows no change on the position of thevacant slot. Therefore, the presence or absence of the disc the in eachdisc storing slot is detected by reading the output pulse train of thedisc presence sensor 50b in synchronization with the trailing edge ofthe output pulse train of the slot postion sensor 50a. The number of thethus detected slot is then memorized in the memory part of the RAM 402(FIG. 10) and will be reviewed at the time of the selection of discs.When the detection of the presence of the disc in each of the discstoring slots is completed, then the carrier is returned to the homeposition and the selection of music is permitted afterwards. Further,the system may be constructed so that the detection of the presence ofthe disc is started in response to the throw-in of the power current,and also it is possible to provide a command switch for starting thedisc presence detection operation so that the detection is started inresponse to the operation of this command switch.

The way of the selection of the music piece is firstly, to use thenumber keys 7 of the control unit 6 to set the disc number and the musicnumber in order. The other way of the selection of the music piece is touse the index plates 13 and the index keys 15 to select the desired discby turning over the index plates 13, and to use the number keys 7 to setthe music number.

As an example, it is assumed that the fifth music program of the thirddisc and the tenth music program of the twenty third disc of the storeddiscs are to be set by the first way of selection. In that case, themanner of the setting operation is as illustrated in FIG. 12A, in whichthe corresponding ones of the number keys 7 and the ENT key are pressedin order before pressing the START key. On the other hand, if the thirdmusic program of the eighth disc and the fifth music program of thethirty third disc are to be set by the second way of selection, theindex plates 13 are in turn turned over until an index plate 13 on whichthe desired disc number is entered is opened as illustrated in FIG. 12b.It is to be noted that the index switches 14 are interlocked with theindex plates and actuated when the index plates 13 are turned over.Thus, the connection of the index keys 15 are automatically altered asthe turning of the index plates 13. Then the index key 15 correspondingto the number of disc to be selected (shown by hatching) is pressed andthe music program number is set by using the number keys 7. As theprevious way, the ENT key is pressed at the end of setting of the firstmusic program, and the second music program is set in the same manner asabove, and in which the index plate 13 is opened as shown in FIG. 12c.The whole operation of this setting process is illustrated in FIG. 12D.

When the entering of the disc number and the music program number of oneof the above mentioned method is completed and the START key 10 ispressed, then the ACCESS indicator 20 lights up and each part of thesystem starts to operate.

The operation will be explained with reference to the flow chart of FIG.13 hereafter.

In response to a start command entered by the START key 10, the carrierassembly 64 is moved to the position of the selected disc. In thisstate, the cam pin 74 securely fixed on the stopper arm 72 of the discstopper 71 is graduarry disengaged from the cam plate 73 of the carrier40 as the carrier assembly 64 moves. As the result, disc stopper 71 forpreventing the backward movement of the stored discs is rotated in thecounter clockwise direction from the position illustrated in FIG. 6B tothe siding position in which the disc can be drawn to the playingposition without contacting with the disc stopper 71 as illustrated inFIG. 7. As the carrier assembly 40 moves, the number displayed on theDISC indicator 16 increases by one and stops a the number correspondingto the selected disc, and the ACCESS indicator 20 is turned off duringthis period.

When the carrier assembly is stopped at the predetermined position, theslider 58 for the loading of the disc to the playing position starts tomove. As the slider 58 moves, the STAND BY indicator 19 lights up. TheSTAND BY indicator 19 is turned on until the disc is loaded on the turntable 100, the disc drive motor 54 starts to rotate, and the playing ofthe music is started.

The operation of the slider part will now be explained with reference toFIG. 14. When the carrier 40 is stopped at the position of the selecteddisc, a drawer roller 78 and a reset roller 79 disposed on the slider 58are in the position as illustrated in FIG. 14A. In this state, theslider motor 80 starts to rotate to move the slider backwards (in thedirection shown by the arrow in the figure). By this movement, thedrawer roller 78 comes to contact with the peripheral edge of the discand moves the disc as the movement of the slider 58 to the playingposition in which the disc is supported on the guide support 43 providedto the carrier 40 and having a slope 43a, and then catched by theclamper 62. Thus, the disc carried by the slider 58 is set on the guidesupport 43. Afterwards, the slider 58 is further moved beyond the discset position, so as to provide a play S between the roller 78 or 79 andthe periphery of the disc. Within this play S, the disc clampingoperation to be explained later is performed.

During the loading of the disc, the slider 58 turns on the detectionposition switch 89c by means of the cam portion 58a thereof. In responseto this turning-on of the detection position switch 89c, the discpresence/disc side sensor 61 disposed on the guide plate 60s is operatedas illustrated in FIGS. 15A and 15B. If the disc is not present or thedisc is placed reversely, then the direction of the movement of theslider 58 is turned over to return the disc in the disc storing part 32.At the same time, the ERROR indicator 21 lights up. If the disc has beenset properly, the disc loading operation is continued and the disc isset in the playing position.

When placed in the playing position, the disc 2' is held on the guidesupport 43 at a level in which the center of the disc is higher thanthat of the discs 2 stored in the disc storing part 32 by an amount t₁.After the disc is set in the playing position, during the movement ofthe slider 58 providing said play S, the guide pin 96 fixed on the clamparm 63 is catched in the guide slot 97a of the engaging member 97 fixedon the slider 58. As the result, the clamp arm 63 is rotated in theclosing direction (counter clockwise direction). As the rotation of theclamp arm 63, the head portion of the clamper 62 passes through thecenter hole of the disc and is then inserted in the turntable 100. Atthe time of insertion, the magnetic element 99 on the head portion ofthe clamper 62 is attracted by the yoke 102 in the turntable 100, andthe tapering portion 62a of the clamper 62 raises the disc 2' on theguide support 43 and the disc 2' is pressed to the face 100a of the turntable 100. In this state, the center of the disc 2" loaded on the turntable 100 is slightly higher than the position of the center of the disc2' placed on the guide support 43 by an amount of t₂ (t₂ <t₁, see FIG.16).

When the loading of the disc on the turntable is completed, the sliderlimit switch 89b is turned on to detect the completion of the clamping(the slider limit switch 89a detects that the slider 58 is in the homeposition). In response to the turning on of the slider limit switch 89b,the disc drive motor 54 starts to rotate. When the speed of the discdrive motor 54 has reached a predetermined level, the pickup 55 is movedat a high speed to the postion of the beginning of the designated musicprogram. During this time, the ACCESS indicator 20 lights up and thePROGRAM indicator 17 indicates increasing numbers and finally indicatesthe number of designated music program at the same time as the pickup 55is stopped at the position. From this position, the pickup 55 is movedat a predetermined constant speed to start the playing of the music.During playing, the STAND BY indicator 19 and ACCESS indicator areturned off, and in turn the PLAY indicator 18 lights up.

When all of the programmed music pieces have been played, the PLAYindicator 18 is turned off and the pickup 55 is returned to the homeposition. After that, the disc 2 is released from the clamper 62 and theturntable 100 and returned to the disc storing part 32. At the sametime, the content of the memory of the RAM 65 which memorizes the numberof the playing times whthin a predetermined period per disc is increasedby one (+1). Then the carrier assembly 64 is moved back to the homeposition.

If a command for altering the order of the arrangement of discs which,for example, can be enterred by means of a switch provided in thecontrol unit 6, is applied to the CPU 603, then the CPU 603 reads from amemory area of RAM 605 the number of times of playing during a periodfrom a certain time in the past to the present time per disc. Then theCPU determines a new order of arrangement of discs in such a manner thatthe most frequently played disc is placed in a store position closest tothe home position of the carrier assembly 64 and the least frequentlyplayed disc is placed in a store position farthest from the homeposition. Further, the CPU 603 temporarily stores the data of thecorrespondence between the disc number (numbers assinged to each disc)and the number of storing position (numbers assinged to each storeposition) into the other memory area of the RAM 605.

Then the CPU 603 compares the new correspondence with an oldcorrespondence between the disc number and the number of the storeposition, and performs the rearrangement of the discs by moving thecarrier assembly and utilizing the vacant slots 200 provided in the discstoring part 32 (shown in FIG. 3). When all of the discs are rearrangedand the actual order of arrangement of the discs becomes diential withthe order of the arrangement of the discs memorized in the memory part,the temporarily stored correspondence between the disc number and thenumber of the storing position is memorized in place of the oldcorrespondence. At the same time, data of the number of playing timesfor each disc is cleared.

Althrough the vacant slots to be used only during the rearrangement ofthe discs are provided in the above example, the same operation can beenabled with the normal arrangement of the disc storing part of thenumber m of the discs is smaller than the number n of the disc storingslots or positions (n≧m+1). Further, the vacant slots 200 becomesunnecessary if the carrier 40 is designed to carry a plurality of discsat the same time.

In addition, instead of the number of times of playing, the number oftimes of selecting a disc can be used as the standard for therearrangement. Further, by memorizing the playing (or selecting) datetogether with the above data, the standard of rearrangement will be a"weighted number of playing (selecting) times". With this method, itbecomes possible to give a priority of determination of the position, todiscs played or selected more recently, to realize more effectiverearrangement in the practical use of the system. Further, the time ofrearrangment is not limited to the avove example, and the rearrangementcan be performed when the playing of the disc is taking place. Further,it is possible to design the system that that the rearragnementautomatically performed when a predetermined time period has elapsed.

It is to be noted that the disc playing system of the present inventionhaving the above explained consturction can be used for playing discs ofvarious sizes. When the invention is applied for the playing system ofthe so called "compact disc" i.e. a digital audio disc, there will be agreat advantage that the size of the playing system is by far reduced ascompared with conventional "jukebox". Moreover, though the invention hasbeen described by taking example of the system in which the disc playingmeans including the pickup 55 is incorporated in the carrier 40, theinvention can be applied to a system in which the disc playing means isprepared separately from the carrier as a stationary unit. In that case,a carrier corresponding to the carrier 40 of the above example may beused only for the transmission of the disc, and a slider correspondingto the slider 58 may be used for transmitting the disc both between thedisc storing part and the carrier, and between the carrier 40 and thedisc playing means. Further, the invention can be applied to suchsystems in which the disc playing means is carried by the slider to thedisc storing part, and the disc is brought over to a state for playing.

In the example of FIGS. 5A through 5D, the sensors 50a and 50b arespaced with each other in the direction of the disc arrangement.However, it is also possible to arrange these sensors in verticalrelation with each other on the holder 51. In addition, if a lightreflective material is used for the shutter 38b, then the light emittingelement and the light receiving element of these sensors will be on thesame side with respect to the shutter 38. Further, these sensors are notlimited to the optical sensor and various types of sensors such as apressure responsive sensor and a contact sensor may be used therefor.

As described in detail hereinabove, the disc playing system of thepresent invention is provided with means for detecting the presence of adisc in each of the disc storing slot of the disc storing part, whichmeans includes a displacement members provided to each of the discstoring slot and to be moved when a disc is placed in the slot, and asensor movable along the direction of the arrangement of the discs todetect the position of each displacement member in order. Therefore, theactuation of the slider is no more required for the detection of thedisc presence, and the vacant slot is detected at vary high speed. Thus,it becomes possible to select the disc storing slots in which a disc isheld, by memorizing the number of vacant slot in the memory means, andaccordingly the playing of musics is performed very smoothly.

What is claimed is:
 1. A disc playing system for playing selected ones of a plurality of stored discs in succession, comprising:disc storing part having a plurality of slots for receiving a disc which are juxtaposed in a predetermined direction with a predetermined pitch, where a sequential number is assigned to each of said slots; a detection means for detecting whether or not a disc is present in each of said slots; and a memory means for memorizing the number of vacant slots in accordance with an output signal from said detection means, wherein said detection means includes a plurality of members movably provided in each of said slots and to be shifted when a disc is put in the slot, and a sensor means movably disposed along said direction of arrangement of slots for in turn detecting the position of each of said members. 